1. Field of Invention
The present invention relates to a scanner and a scanning method. More particularly, the present invention relates to a multiple-field sensor for image scanning.
2. Description of Related Art
Due to the rapid development of multimedia technologies, image processing speed and clarity have become an important consideration in the selection of a scanner by users. However, a scanner operates according to light reflected from a document. Hence, outside light or any irregular dispersion, diffraction may lead to certain degree of distortion for a scanned image. In addition, limitations in the manufacturing of sensors also contribute to the production noise signals that further distort the image.
An attempt to deal with image distortion problem has been proposed in the Taiwan Patent No. 385608. In the invention, a sensor is used to scan a document a multiple of times to obtain a multiple of scanned images. Thereafter, the scanned images are averaged to reduce the amount of distortion to the actual image. However, this and similar type of designs require multiple scanning and the sensor has to shuttle forward and backward many times. Hence, the scanning is time-consuming and highly inefficient.
In brief, common defects of conventional scanning techniques include:                1. The scanned image is likely to be distorted if noise signals contained within the image are untreated; and        2. If the scanned image is treated by scanning the same documents a few times using the same sensor, the sensor has to shuttle many times leading to time wastage and hardware control problems.        